573 research outputs found
PP-OMDS: An Effective and Efficient Framework for Supporting Privacy-Preserving OLAP-based Monitoring of Data Streams
No full textPP-OMDS: An Effective and Efficient Framework for Supporting Privacy-Preserving OLAP-based Monitoring of Data Stream
Discussion - An empirical model of fatalities and injuries due to floods in Japan by Guofang Zhai, Teruki Fukuzono, and Saburo Ikeda
No full text[No abstract available]ASAAF H, 2002, P CAN DAM ASS CDA 20; ASSAF H, 2001, WORLD WAT ENV RES C; BROWN CA, 1988, WATER RESOUR BULL, V24, P1303; DEKAY ML, 1993, RISK ANAL, V13, P193, DOI 10.1111-j.1539-6924.1993.tb01069.x; JONKMAN SN, 2002, FLOOD DEFENCE 2002, P196; MILLER DM, 1984, AM STAT, V38, P124, DOI 10.2307-268324712
Privacy-Preserving OLAP-based monitoring of data streams: The PP-OMDS approach
No full textIn this paper, we propose PP-OMDS (Privacy-Preserving OLAP-based Monitoring of Data Streams), an innovative framework for supporting the OLAP-based monitoring of data streams, which is relevant for a plethora of application scenarios (e.g., security, emergency management, and so forth), in a privacy-preserving manner. The paper describes motivations, principles and achievements of the PP-OMDS framework, along with technological advancements and innovations. We also incorporate a detailed comparative analysis with competitive frameworks, along with a trade-off analysis
Pseudorandom Self-Reductions for NP-Complete Problems
No full textA language L is random-self-reducible if deciding membership in L can be reduced (in polynomial time) to deciding membership in L for uniformly random instances. It is known that several "number theoretic" languages (such as computing the permanent of a matrix) admit random self-reductions. Feigenbaum and Fortnow showed that NP-complete languages are not non-adaptively random-self-reducible unless the polynomial-time hierarchy collapses, giving suggestive evidence that NP may not admit random self-reductions. Hirahara and Santhanam introduced a weakening of random self-reductions that they called pseudorandom self-reductions, in which a language L is reduced to a distribution that is computationally indistinguishable from the uniform distribution. They then showed that the Minimum Circuit Size Problem (MCSP) admits a non-adaptive pseudorandom self-reduction, and suggested that this gave further evidence that distinguished MCSP from standard NP-Complete problems.
We show that, in fact, the Clique problem admits a non-adaptive pseudorandom self-reduction, assuming the planted clique conjecture. More generally we show the following. Call a property of graphs π hereditary if G ∈ π implies H ∈ π for every induced subgraph of G. We show that for any infinite hereditary property π, the problem of finding a maximum induced subgraph H ∈ π of a given graph G admits a non-adaptive pseudorandom self-reduction
Crisis and catastrophe: the motor of South African history?
No full textMP4 Video; Size: 3.34GB; Duration: 1:05Please cite as: Academy of Science of South Africa (ASSAf), (2021). Crisis and Catastrophe: The Motor of South African History?. [Online] Available at: http://hdl.handle.net/20.500.11911/201Annual Humanities Lecture Webinar hosted by the Academy of Science of South Africa (ASSAf) on 5 October 2021. Presented by Assistant Prof Jacob Dlamini, Princeton University, United States of America.
In 1977, R.W. Johnson published How Long will South Africa Survive?, a book that sought to examine the resilience of what the author called South Africa’s ‘White Establishment.’ Johnson challenged the tendency among left-wing thinkers and Afrikaner nationalists to see change in South Africa as being driven solely by the internal dynamics of the country’s history. As Johnson elaborated in a 2015 sequel to How Long will South Africa Survive?the ‘iron law’ of South African history was that international developments have always been more responsible for change in the country; that crises generated by South Africa’s position in the global economy have always been the key driver of political transformation in the country. In my presentation, the presenter built on Johnson’s claim that crisis (and catastrophe) is the motor of South African history. He used his claim to position South Africa as a vantage point from which to imagine a national history not burdened by race, and to tell a South African story that is at the same time a global history of the 20th-century. What happens to conventional accounts of South African history (not to mention global history) when we treat the country as the standpoint from which to examine some of the major crises and catastrophes of the 20th century? That is the question at the centre of this presentation.Academy of Science of South Africa (ASSAf
Potential Function Analysis of Greedy Hot-Potato Routing (Extended Abstract)
No full textAmir Ben-Dor Shai Halevi y Assaf Schuster z January 21, 1994 Abstract In this work we study the problem of packet routing in synchronous networks of processors, in which at most one packet can traverse any communication link in each time step. We consider a class of algorithms known as hot-potato or deflection routing algorithms. The important characteristic of these algorithms is that they use no buffer space for storing delayed packets. Each packet, unless already arrived to its destination, must leave the processor at the step following its arrival. The main advantage in hot-potato routing is that there is no need to store delayed packets in the processors, and therefore, the processors can be much simpler, and contain less hardware. This work is concerned with greedy routing, in which a packet is bound to use an out-going link in the direction of its destination, whenever such a link is available. In this way, greediness guarantees that, unless some global congestion forbids..
A hydro-economic model for managing groundwater resources in semi-arid regions
No full textAccess to fresh water resources is a limiting factor in the socio-economical development of countries located in semi-arid regions. Water scarcity in these regions, particularly the North Africa and Middle East (MENA) region, is expected to intensify not only due to projected decline in effective precipitation due to climate change and variability, but also due to excessive growth in demand driven by explosive growth in population and improvement in living standards. The meager surface water resources in these regions have already been exploited and significantly polluted leading many governments to deplete their fossil and poorly recharged aquifers mostly to support inefficient and unsustainable agricultural policies and heavy subsidy of municipal water demand. The paper presents an interactive decision support model developed based on economic principles and simple aquifer representation using the STELLA system dynamics development environment. The model is designed to help water policy makers and managers and other stakeholders formulate and assess alternative water allocation policies among the municipal, industrial and agriculture sectors. Model users will be able to set and interactively manipulate key parameters that influence economic values and sustainability of alternative water policies. These parameters are associated with energy prices, discount rates, planning horizon, demographic factors, willingness-to-pay, hydro-meteorological conditions, aquifer characteristics, and industrial water productivities cropping patterns and agricultural water productivities. Long-term projections of economic value, withdrawals, and remaining water stocks in addition to water demand are presented in tabular and graphical forms. The paper presents a case application of the model for managing the Amman-Zarqa aquifer in Jordan. The aquifer is considered a crucial water resource in water poor Jordan. © 2009 WIT Press.ABDULLA F, 2008, WATER RESOURCES MANA; Assaf H, 2008, ENVIRON MODELL SOFTW, V23, P1327, DOI 10.1016-j.envsoft.2008.03.006; Chebaane M, 2004, HYDROGEOL J, V12, P14, DOI 10.1007-s10040-003-0313-1; GISSER M, 1983, J POLIT ECON, V91, P1001, DOI 10.1086-261197; Griffin R.C., 2006, WATER RESOURCE EC; *ISEE SYST, STELLA SYST THINK ED; Schiffler M., 1998, EC GROUNDWATER MANAG; Winz I, 2007, P 25 INT C SYST DYN1
‘Twelve Years Later: Second ASSAf report on Research Publishing in and from South Africa (2018)’: Some issues arising
No full textAbstract:Responding to the extraordinary challenges facing publication in the digital age is the holistic view taken by the Academy of Science of South Africa (ASSAf) on threats and opportunities that characterise this conjuncture. Twelve Years Later, researched by Wieland Gevers, Robin Crewe and Susan Veldsman on national publishing strategies, provides the ‘nuts ’n bolts’ that every researcher should know in order to navigate the changing environment.1 The Report examines both past and present. The first chapter reviews ASSAf’s 2006 report.2 Chapter 2 revisits the 2009 report on books. Chapter 3 details ASSAf’s Scholarly Publishing Programme between 2007 and 2018. How to enhance access of South African authors to global commercial publishers is discussed in Chapter 4. Chapter 5 deals with journal and book publishing, and Chapter 6 examines pitfalls and threats to good publishing practices. Outstanding problems are highlighted in Chapter 7. Chapter 8 offers recommendations. Appendices (45 pp) tabulate the hard data on which the study draws. These data showcase close correlations between the ASSAf qualitative evaluations and Department of Higher Education and Training (DHET) decisions. Significantly, ASSAf ratings and reviews of publishers closely align with the international Socio-economic and Natural Sciences of the Environment (SENSE) and the Norwegian Register for Scientific Journals, Series and Publishers ratings. The 2018 Report offers a detailed history useful for individual university policy planning, and implementation of monitoring mechanisms, and explains accreditation decisions. A basic cost–benefit analysis of the publication incentive system administered by DHET identifies residual problems. Notwithstanding these (see below), the statistics tabulated in Appendices by the Centre for Research, Evaluation, Science and Technology (CREST) at Stellenbosch University reveals that DHET has been very effective in encouraging publication. It has also acted as an inhibiting factor in author choice of predatory journals, although many thousands of articles still slipped through...
Randomized Single-Target Hot-Potato Routing
No full textWe present randomized hot-potato routing algorithms on d-dimensional meshes and on the n-dimensional hypercube. The algorithms are designed for routing many packets to a single destination, or a relatively small number of destinations. The important feature, which was not obtained previously, is that the algorithms utilize the higher in-degree of the nodes and are asymptotically optimal. A preliminary version was presented at the 3rd ISTCS 1995 (Israeli Symp. on the Theory of Computing Systems). y This work was supported in part by the French-Israeli grant for cooperation in Computer Science, and by a grant from the Israeli Ministry of Science. z Department of Computer Science, Technion, Haifa, Israel 32000. E-mail: [email protected] x Mathematics and Computer Science, Haifa University, Haifa, Israel 31905. E-mail: [email protected] -- Department of Computer Science, Technion, Haifa, Israel 32000. E-mail: [email protected] 1 Introduction In this work we..
1 BOUNDS AND ANALYSIS TECHNIQUES FOR GREEDY HOT-POTATO ROUTING
No full textABSTRACT In this chapter we consider a type of packet routing known as hot-potato routing. In hot-potato routing there is no intermediate storage for the packets (messages) that are on their way to their destinations, which is an important feature for communication networks that are based on optical hardware and for which the messages are composed of beams of light. In particular we consider a "practical " mode of routing, known as greedy routing. In greedy routing, unless some local congestion forbids it, an intermediate network node always attempts to send packets towards their destinations. We present several algorithms and analysis methods that were recently suggested by the author and his colleagues for greedy routing, along with some negative results by means of a general lowerbound
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